This is how you do it mrdh

Just press 'esc' in game then click the video tab in 'options' Just be carefull you dont make ur screen go to a res that puts the options off the edge of the screen.
I went into video options and selected widescreen 16/9 840xsummit by accident, applyed it then changed it back to standard width 1600x1200 and it makes the icons and chat go small.